Wood stains containing a flavanone azo dye



United States Patent Ofiice WOOD STAINS CONTAINING A FLAVANONE AZO DYEHarry A. Toulmin, Jr., Dayton, Ohio, assignor to Chadeloid Corporation,Dayton, liio No Drawing. Application May 29, 1953, Serial No. 358,554

'6 Claims; (Cl. 8-6.5)

This invention relates to stains, especially stains for use on wood andto compositions for use in staining wood articles and the like, as wellas methods for staining such articles.

The art of wood staining in the past has made use of dyes which weredissolved or dispersed solvents and the like diluents so as to makethesame applicable for applying as a spray, dip, or by brush. The watersoluble' stains generally consisted of an aqueous solution of an"aniline dye, and were applied by brushing the same onto the wood surfaceto be stained. Such water stains, how ever, exhibit the very undesirableeffect of raising the grain of the wood. This raising of the grainnecessitates that the surface be sanded or otherwise treated to renderit smooth. The grain raising effect of such water soluble stains alsomakes it necessary to apply a sealer coating such as shellac to thestained wood in order to stiffen the fibers of the wood so that thesurface can be uniformly sanded. When an open grain wood is used, it isnecessary, after the sanding operation, to apply a filler to the surfaceover which is then applied a varnish, lacquer or other desired coating.7

The non-aqueous stains, for example, oil stains and spirit stains, andwhich generally 'consist of an'aniline dye or aniline dye basedissolvedin an organic solvent such as a hydrocarbon or alcohol, havebeen extensively used and have certain advantages over water stains.They also have certain undesirable features.- The use of hydrocarbons,such as benzol, toluol or other petroleum distillates that are highlyvolatile when applied to the surface to be treated tends-t leave thepores of the wood- They are also dangerous the solvents of the varnishor lacquer will penetrate into the stain and cause the color to bleedinto thefinish coat. Theuse of hydrocarbon solvents also is undesirablefrom the standpointv of fire hazard and the effect thevolatile solventmay have on the operator applying the stain.

The spirit stains are not as useful as the water stains because they aresubject to the disadvantage that such. stains-do not penetrate into thewood stains and they further lack permanency of color and tend to fadein. use, similar as the oil. type stains. Spirit stains are also subjectto. the bleeding effect, and in manyinstances, also produce theundesirable grain raising upon application to the wood surface.

In accordance with the present invention, I have discovered that. bycombining citrus flavanone derivatives, for example, hesperetin ornaringenin found in citrus pulp and citrus waste, with'aniline oraniline bases, and

Thisapplication of shellac or the like is necessary, otherwisedispersingthe resultant dye in water solution that this new combination providesan excellent wood stain composition With unexpected results. Thiscitrus-aniline dye compound can be readily fixed in the cellulose poresof the wood as it is derived from cellulose and is compatible with it.

It may be applied as a hot or cold solution to the wood. A hot aqueoussolution of such citrus-azo dyes as derived from these citrusfiavanone's obtained from citrus wastes, being derived from a cellulosesource, forms a stain which is completely compatible with the wood sothat a highly desirable stain effect is produced with completedispersion of uniform character'and deep penetration. 1

The aqueous staining solutions of this invention which comprise theaforementioned citrus-azo dye are preferably applied as a hot aqueoussolution, although it is also efifectivevas a wood stain when applied asa'cold solution.- Hot aqueous solutions of such dyes when appliedpenetrate into the wood and the solvent evaporates before the grain ofthe wood is caused to raise;

Upon cooling, the dye is set in the Wood and forms a smooth uniformlystained wood surface which requires nosanding orother treatment toproduce a desirable surface upon'which a finish coating of varnish orlacquer may be applied; 1

v disadvantages, may be: entirely eliminated.

A typical formula of naringenin is as follows;

The combination: citrus-azo dyes which are utilized informing the-'wood"staining compositionof "this inventionare exemplified bythe followingcompounds which are illustrated graphicallyas follows: A

Coupling aniline with naringenin, e. g., recovered from grapefruitwaste, as described results in the production,

of an azo dye having the probable structural formula:

Patented Nov. 15, 1955' the production of an azo dye having the probablestructural formula:

In accordance with the present invention, I have found that these azodyestufls can be obtained by coupling a diazotized aromatic aminocompound, preferably one containing at least one substituted benzenenucleus or a naphthalene nucleus, with a polyhydroxy flavanone, forexample naringenin, eriodictyol or hesperetin, such as derived fromcitrus waste products. The resultant dyestuffs, which are water soluble,are of particular value in compounding wood stains.

The object of coupling into a new compound of the naringenin andhesperetin with a diazotized aromatic amino compound to produce acarrier on which the dye compound may be fixed in suitable colors of thebrowns, yellows, and reds of varying hues and shades.

These citrus dyes are soluble in methanol to a limited degree and arevery slightly soluble in Carbitol Cellusolve. They are insoluble inhydrocarbons, esters and higher alcohols. Higher temperatures do notincrease solubility in solvents.

Therefore, the advantage lies in the fact that with the dyes beinginsoluble in the customary solvents, it is possible to provide a rapidlyvolatizing organic solvent in which the dye is substantially insoluble;and to provide a wood stain that, when it is once applied, is notsubject to injury by the hydrocarbons, esters, alcohols, etc. The watersolution of the dye, therefore, maintains its integrity despite theassociation with it in application of rapidly volatizing organicsolvents or in use with glycols, ethers, alcohols and the benzene seriesof hydrocarbons.

These dyes stained the wood well, with good clarity and non-bleedinginto succeeding coats. The darker dyes are more soluble than the reddyes. The darker dyes can be made in as high as a ten ounce solution ascontrasted with the usual two ounce solution in the lighter dyes.

Illustrative of the method of producing the diazo dyes for use inpreparing aqueous wood stains is as follows:

Example I 1. To a slurry comprising 0.1 mol of aniline in water is added0.25 mol of hydrochloric acid. The mixture is diluted with water andcooled'to a temperature of between about -15 C.

While maintaining the temperature of the mixture" at about 10 C., thereis added slowly over a period of about 10 to 15 minutes a 0.1 mol sodiumnitrite. The mixture is stirred slowly while maintaining the temperatureat about 10 C. for one-half an hour.

2. To effect the coupling reaction, a solution containing 0.1 mol ofhesperetin dispersed in an aqueous solution containing 0.3 mol of sodiumhydroxide is employed. The mixture is diluted with water and cooled tobetween and C. Thereafter, the diazo of (1) is stirred into the mixtureover a minute period while maintaining the temperature at about 10-15"C. and the pH of the solution above 9. After stirring the mixture forhalf an hour more the dyestulf is isolated by adjusting the pH of thesolution to neutral with dilute hydrochloric and adding a salt, i. e.,sodium chloride or sodium sulfate, until the dye precipitates from thesolution. Thereafter, the mixture is filtered to recover the dyestuff.

Example II In this example, aniline is diazotized in the usual mannerand coupled with naringenin (or a mixture of naringenin and hesperetin)as the flavanone substance.

Example III Variations of naringenin azo dyestuffs are made by carryingout the coupling as described in Example I employing other amines oramino compounds in place of aniline, such as l-naphthamine 4 sulphonicacid, 2 amino 8 naphthol sulfonic acid and p-nitroaniline.

Example IV Similarly variations of hesperetin azo dyestutfs are preparedby effecting a coupling action as described in Example I utilizinginstead of aniline, other amino compounds such as l-naphthalene4-sulfonic acid, Z-amino- S-naphthol 6-sulfonic acid.

The invention broadly includes the preparation of wood stainingcompositions comprising a water-soluble azo dyestuff containing thegrouping AN=NB in which A represents the residue of an aromatic aminocompound and B is a flavanone derivative of citrus wastes as describedabove. N is nitrogen.

Varied shades of color may be produced with the citrus azo dyestuffs,depending on the particular amine and flavanone used in compounding thedyestuff.

The following examples are exemplary of the specific wood stainingcompositions in accordance with the present invention:

Example V A wood stain is prepared by dissolving the product of ExampleI in water to form a 5% solution. The resulting stain may be applied towood by brushing or spraying.

Example VI To a gallon of water is added one ounce of the dyestuffsprepared as described in Example I.

Example VII Suitable amounts of the dyestuffs, as described in ExamplesIII and IV, are dissolved in water to provide a staining compositionhaving the desired strength.

The amount of dye utilized in a given case depends upon the particulardye employed, and its degree of concentration, and, of course, the depthof color required for the particular stain.

Additional solvent and vehicle ingredients may be added to the chosencitrus-azo dye (as described in the patent to Bush No. 2,000,121 of May7, 1935) to secure the particular properties desired in the finalcomposition. In choosing such additional solvents or diluents or othervehicles, several factors should be kept in mind. The solvents ordiluents or additional vehicles utilized should preferably beinexpensive enough to make them commercially practicable for the use inhand. They should be solvents of or miscible with the dye dissolved inthe penetrant vehicle component, and should be of such nature as topenetrate the wood and carry the dye into the wood. Further, thecomposition should desirably include a water eliminant in order to givethe composition properties of resistance to moisture retention. Further,the combination of solvents or diluents or vehicles should be such thatthe final composition exhibits a proper evaporation curve to dispel boththe diethylene-glycol monoethyl ether or other penetrant vehicle and anymoisture present from the wood surface.

As illustrative of ingredients that may be utilized in order to increasethe rapidity of drying and setting of the composition, the aliphaticalcohols, such as methyl alcohol, ketones, such as acetone, and theesters of the aliphat c alcohols, particularly the fatty acid esters ofsuch but such materials as these esters are slower drying and cost more,and, therefore, are not as valuable in general in compositions of thepresent character as are the hydrocarbon substances, such as toluol.Both the aliphatic alcohols and similar ingredients and the hydrocarbondistillates, and similar ingredients aid in the penetration andevaporation and other desirable effects above mentioned.

A modified wood staining composition may be made using compositesolvents, such as follows, the parts being by weight:

Parts Diethylene-glycol mono-ether 1-5 Methyl alcohol 8-10 Toluol 4-6This composition may be utilized with, for example, from 2 to 3 ouncesof the particular citrus-azo dye to one gallon of the composite solvent.Diethylene-glycol mono-ethyl ether is a particularly good penetrantvehicle component since these desirable citrus-azo dyes are soluble inthis substance. Mono butyl ether of diethylene glycol may also be usedfor this purpose.

While for the production of stain compositions, par ticularly fortreating wood surfaces, the compositions hereinabove described may beutilized, other additional ingredients may be added to the compositionfor particular purposes. For example, fillers, such as silex, or oilpaste fillers, may be mixed with the new stain composition to make acombination stain and filler.

A combination citrus-azo dye stain and filler having a transparent colorthat is fast to light may, accordingly, be produced under thisdisclosure, whereas this result has never heretofore been possible.

In addition, the citrus-azo dye stains produced in accordance with thisdisclosure, or the stain bases, may be added to or incorporated withcellulose ester or ether solutions and lacquers, as well as otherlacquers, particularly those containing solvents of the nature ofalcohols and hydrocarbons. In this way, color dipping lacquers, thecolor of which is fast, may be produced. Various types of nitrocellulosecompositions may, for example, be combined with the stain bases orcompositions of the present invention.

In accordance with the present invention, it is possible for the firsttime to utilize such water soluble azo dyes made by coupling a fiavanonederivative, such as naringenin, eriodictyol or hesperidin with anilineor other suitable diazotizing amino compound to form a water soluble dyewhich yields, upon dispersion in an aqueous vehicle, a wood stain whichis substantially fast to light, and exhibits non-fading, non-grainraising properties. A wood stain also is provided which, when properlycompounded and applied as described, ates not bleed through'lacquer orvarnish top finishing coats. Thus, the use of intermediate sealing coatsis not necessary. Where desired, of

course, intermediate sealing coats of suitable type may be employed.

This application relates to applicants prior application Serial Number277,921 filed March 21, 1952.

It will be understood that While there have been described hereincertain specific embodiments of this invention, it is not intendedthereby to have it limited to or circumscribed by the specific detailsgiven in view of the fact that this invention is susceptible to variousmodifications and changes which come within the spirit of thisdisclosure and the scope of the appended claims.

I claim:

l. A wood staining composition comprising an azo dye in which thecoupling component is chosen from the group consisting of naringenin,hesperetin and eriodictyol, and comprising a volatilizable organicsolvent chosen from the group consisting of methyl alcohol and loweraliphatic alcohol esters and ethers.

2. A wood staining composition as in claim 1, in which the azo dyeconsists of diazotized aniline coupled with a component chosen from thegroup consisting of narin genin, hesperetin, and eriodictyol.

3. A wood staining composition comprising an azo dye in which thecoupling component is chosen from the group consisting of naringenin,hesperetin and eriodictyol, and comprising a filler and a volatilizableorganic solvent chosen from the group consisting of methyl alcohol, andlower aliphatic alcohol esters and ethers.

4. A wood staining composition comprising an azo dye in which thecoupling component is naringenin, and said composition containing avolatilizable organic solvent chosen from the group consisting of methylalcohol and lower aliphatic alcohol esters and ethers.

5. A wood staining composition comprising an azo dye in which thecoupling component is hesperetin, and said composition containing avolatilizable organic solvent chosen from the group consisting of methylalcohol and lower aliphatic alcohol esters and ethers.

6. A wood staining composition comprising an azo dye in which thecoupling component is eriodictyol, and said composition containingorganic solvent chosen from the group consisting of methyl alcohol andlower aliphatic alcohol esters and ethers.

References Cited in the file of this patent UNITED STATES PATENTS901,096 Hall Oct. 13, 1908 1,106,781 Chapin Aug. 11, 1914 1,977,345Moore Oct. 16, 1934 2,000,120 Bush May 7, 1935 2,105,984 Moore Jan. 18,1939 OTHER REFERENCES Perkin, Jour. Chem. Soc., vol. 73 (1898) pp.666-674.

1. A WOOD STAINING COMPOSITION COMPRISING AN AZO DYE IN WHICH THECOUPLING COMPONENT IS CHOSEN FROM THE GROUP CONSISTING OF NARINGENIN,HESPERETIN AND ERIODICTYOL, AND COMPRISING A VOLATILIZABLE ORGANICSOLVENT CHOSEN FROM THE GROUP CONSISTING OF METHYL ALCOHOL AND LOWERALIPHATIC ALCOHOL ESTERS AND ETHERS.